Financing Receivables And Guarantees (Schedule Of Financing Guarantees Outstanding) (Detail) (USD $) In Millions, unless otherwise specified	Oct. 27, 2012	Jul. 28, 2012
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees	$ 615	$ 509
Deferred revenue associated with financing guarantees	(436)	(393)
Maximum potential future payments relating to financing guarantees, net of associated deferred revenue	179	116
Channel Partner [Member]
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees	372	277
Deferred revenue associated with financing guarantees	(221)	(193)
End User [Member]
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees	243	232
Deferred revenue associated with financing guarantees	$ (215)	$ (200)